A computer network is often used within the scope of the data processing of imaging medical-specific systems (postprocessing), to which computer network a number of computers (for instance PCs or workstations) is connected, and said computer network having a shared storage area. The shared storage area is generally embodied as a so-called PACS (=picture archiving and communication system). A PACS can however also be used if only one single computer is available, by which the storage area is accessed.
The computers run applications. Within the scope of running the applications, the computers have read access to the shared storage area. Furthermore, within the scope of running the applications, the computers can in this respect often have write access to the shared storage area as they can store new data in the shared storage area. Files which are already stored in the shared storage area can however neither be changed (and/or overwritten) or deleted by the computer within the scope of running the applications. The files stored in the shared storage area are therefore protected files in terms of the applications. With respect to an individual computer, which runs one of the applications, the computer therefore executes the following actions as a function of corresponding commands, which are prespecified thereto by a user:                It reads files out from the storage area and determines new files on the basis of the read out files.        It stores the newly determined files as protected files in the storage area.        
By contrast, within the scope of running the application, the computer does not cause the files stored in the storage area to be changed, overwritten or deleted. The prespecification of corresponding commands by the user is not possible and/or the execution of corresponding commands is refused.
In the case of several computers, the computer can actually store the files read out from the storage area and/or the files determined thereby temporarily in a storage facility. Access to this storage facility is however only possible by the respective computer. The other computers in the computer network cannot access this storage facility.
The files which are stored in this storage facility are unprotected files. Said files can not only be read out and written for the first time by the first computer within the scope of running the application but can instead also be changed and deleted.
The deletion of files, which are stored in the storage area, is in principle likewise possible. The deletion nevertheless takes place within the scope of running the applications, in other words the programs processing the data. A separate file management program is used herefor in the prior art. The file management program can even run on one of the computers, which also process the applications. It can alternatively run on another computer, which does not process any of the applications. In any case the file management program is not an application.
It proceeds as follows in the prior art: an application on one of the computers is called up by a user. Within the scope of running the application, new files are determined and stored on the basis of files stored in the storage area. The storage either takes place in the shared storage area or in a storage facility, which can only be accessed by the computer running the respective application.
The newly determined files are subsequently required again by an application, which is run at a subsequent point in time. This can be the same application (if this application was still not completely processed) or another application. If the newly determined files are stored in the storage area, the newly determined files can then also be called up if the calling takes place by another computer, by which the files were stored in the storage area. It is however disadvantageous if, within the scope of the further course, it is determined that the newly determined files were created in a suboptimal fashion. Because it is not only the, still problem-free per se, renewed determination of new files that is necessary, there is instead the problem that previously determined files having been found to be suboptimal not being able to be deleted within the scope of running the application, but instead remaining in the shared storage area. As a result, storage space is occupied, which cannot be used for other purposes. Furthermore, it may be that the files judged to be suboptimal are erroneously called up and further processed at a subsequent point in time. The deletion of the suboptimal files is in principle possible, but laborious, time-consuming and often associated with a large time delay and is furthermore not possible within the scope of running the application.
It is by contrast naturally also possible to store the newly determined files in the storage facility, which is only accessed by the computer running the application. In this case, the changing/overwriting and deletion of the files which are found to be suboptimal is readily possible. This is however disadvantageous in that access to the stored files is only possible by the computer which created the files. Access by another computer in the computer network is not possible.
It is theoretically also conceivable to store the files on a mobile data carrier, for instance a mobile hard disk or a USB memory stick. This procedure is however complicated and relatively slow. Furthermore, in this case access to the files is also linked to the computer, with which the mobile data carrier is connected in each instance.